The present invention relates to a method for manufacturing a liquid crystal display panel, and more particularly, to an alignment method for a liquid crystal display panel.
In the TFT-LCD manufacture, there are two alignment approaches mainly utilized in liquid crystal molecule alignment, that is, rubbing treatment and optical alignment. The rubbing treatment will cause static electricity and particle pollution. The optical alignment is a noncontact alignment technology, which utilizes linear polarized light to irradiate a light-sensitive polymer alignment film to form a pretilt angle. Relatively speaking, the optical alignment is a better alignment approach.
FIG. 1 is a schematic diagram showing an existing optical alignment approach. As shown in FIG. 1(a), at the side of a thin film transistor array substrate, an exposing alignment procedure is performed upwardly and downwardly along the long edge of a pixel, and the exposing width is a half of the width of the corresponding pixel; as shown in FIG. 1(b), at the side of a color filter substrate, the exposing alignment procedure is performed leftwardly and rightwardly along the short edge of the pixel, and the exposing width is a half of the length of the corresponding pixel. The directions the liquid crystal molecules incline are indicated by the arrows shown in FIG. 1(c). FIG. 1(d) and FIG. 1(e) show a dark line pattern inside a pixel, where FIG. 1(d) is a simulated result without a black matrix and FIG. 1(e) is a simulated result with the black matrix.
The existing optical alignment approach will form a dark line pattern with a shape of  or , called WAN-ZI dark line pattern, in the inner of a pixel, as shown in FIG. 2. The WAN-ZI dark line pattern seriously affects the aperture ratio of the pixel. The aperture ratio has become a bottleneck in the optical alignment technology, especially as with the increasing of pixel density.
Therefore, there is a need to provide an alignment method for a liquid crystal display panel for solving the technical problem of low light transmission rate due to the dark line pattern in the existing alignment approaches.